Estimated hours taken: 500 or so
This change implements typeclasses. Included are the necessary changes to
the compiler, runtime and library.
compiler/typecheck.m:
Typecheck the constraints on a pred by adding constraints for each
call to a pred/func with constraints, and eliminating constraints
by applying context reduction.
While reducing the constraints, keep track of the proofs so that
polymorphism can produce the tyepclass_infos for eliminated
constraints.
compiler/polymorphism.m:
Perform the source-to-source transformation which turns code with
typeclass constraints into code without constraints, but with extra
"typeclass_info", or "dictionary" parameters.
Also, rather than always having a type_info directly for each type
variable, sometimes the type_info is hidden inside a typeclass_info.
compiler/bytecode*.m:
Insert some code to abort if bytecode generation is used when
typeclasses are used.
compiler/call_gen.m:
Generate code for a class_method_call, which forms the body of a class
method (by selecting the appropriate proc from the typeclass_info).
compiler/dead_proc_elim.m:
Don't eliminate class methods if they are potentially used outside
the module
compiler/hlds_data.m:
Define data types to store:
- the typeclass definitions
- the instances of a class
- "constraint_proof". ie. the proofs of redundancy of a
constraint. This info is used by polymorphism to construct the
typeclass_infos for a constraint.
- the "base_tyepclass_info_constant", which is analagous the
the base_type_info_constant
compiler/hlds_data.m:
Define the class_method_call goal. This goal is inserted into the
body of class method procs, and is responsible for selecting the
appropriate part of the typeclass_info to call.
compiler/hlds_data.m:
Add the class table and instance table to the module_info.
compiler/hlds_out.m:
Output info about base_typeclass_infos and class_method_calls
compiler/hlds_pred.m:
Change the representation of the locations of type_infos from "var"
to type_info_locn, which is either a var, or part of a typeclass_info,
since now the typeclass_infos contain the type_infos for the type that
they constrain.
Add constraints to the pred_info.
Add constraint_proofs to the pred_info (so that typeclass.m can
annotate the pred_info with the reasons that constraints were
eliminated, so that polymorphism.m can in turn generate the
typeclass_infos for the constraints).
Add the "class_method" marker.
compiler/lambda.m:
A feable attempt at adding class ontexts to lambda expressions,
untested and almost certainly not working.
compiler/llds_out.m:
Output the code addresses for do_*det_class_method, and output
appropriately mangled symbol names for base_typeclass_infos.
compiler/make_hlds.m:
Add constraints to the types on pred and func decls, and add
class and instance declarations to the class_table and instance_table
respectively.
compiler/mercury_compile.m:
Add the check_typeclass pass.
compiler/mercury_to_mercury.m:
Output constraints of pred and funcs, and output typeclass and instance
declarations.
compiler/module_qual.m:
Module qualify typeclass names in pred class contexts, and qualify the
typeclass and instance decls themselves.
compiler/modules.m:
Output typeclass declarations in the short interface too.
compiler/prog_data.m:
Add the "typeclass" and "instance" items. Define the types to store
information about the declarations, including class contexts on pred
and func decls.
compiler/prog_io.m:
Parse constraints on pred and func declarations.
compiler/prod_out.m:
Output class contexts on pred and func decls.
compiler/type_util.m:
Add preds to apply a substitution to a class_constraint, and to
a list of class constraints. Add type_list_matches_exactly/2. Also
add typeclass_info and base_typeclass_info as types which should not
be optimised as no_tag types (seeing that we cheat a bit about their
representation).
compiler/notes/compiler_design.html:
Add notes on module qualification of class contexts. Needs expansion
to include more stuff on typeclasses.
compiler/*.m:
Various minor changes.
New Files:
compiler/base_typeclass_info.m:
Produce one base_typeclass_info for each instance declaration.
compiler/prog_io_typeclass.m:
Parse typeclass and instance declarations.
compiler/check_typeclass.m:
Check the conformance of an instance declaration to the typeclass
declaration, including building up a proof of how superclass
constraints are satisfied so that polymorphism.m is able to construct
the typeclass_info, including the superclass typeclass_infos.
library/mercury_builtin.m:
Implement that base_typeclass_info and typeclass_info types, as
well as the predicates type_info_from_typeclass_info/3 to extract
a type_info from a typeclass_info, and superclass_from_typeclass_info/3
for extracting superclasses.
library/ops.m:
Add "typeclass" and "instance" as operators.
library/string.m:
Add a (in, uo) mode for string__length/3.
runtime/mercury_ho_call.c:
Implement do_call_*det_class_method, which are the pieces of code
responsible for extracting the correct code address from the
typeclass_info, setting up the arguments correctly, then executing
the code.
runtime/mercury_type_info.h:
Macros for accessing the typeclass_info structure.
Estimated hours taken: 4
Translated plain text docs to HTML. This obviously creates
a dual update problem. We should solve this by putting
the plain text docs in the attic and retaining the HTML.
Also added the HTML files to the Mmakefile so they are installed
on the web pages.
The other documents in compiler/notes will be HTMLized soon.
compiler/notes/
Mmakefiles
ALLOCATION.html
AUTHORS.html
CODING_STANDARDS.html
COMPILER_DESIGN.html
GC_AND_C_CODE.html
GLOSSARY.html
MODULE_SYSTEM.html
RELEASE_CHECKLIST.html
REVIEWS.html
TODO.html
